My build is mostly an AS build do to twitches great attack speed and great abilities to gank enemy champions with. The idea is to get as more hits on the enemy faster then they can hit you.
Meaning when you get in a fight, finish it ASAP, but watch out twitches abilities aren't really power full so throw in a good one or two ability power increasing items or maybe even get a few runes that will have the same effect. Not only is twiche's attacks fast but they are also weak so this build might be counted as an AP/AS/AD build hybrid if you would like to.
(P.S. My first build published so if you would not be to mean at it but please give some helpful advise on how to get these builds better. peace)